'use strict'
const path = require('path')
const defaultSettings = require('./src/settings.js')

function resolve(dir) {
  return path.join(__dirname, dir)
}
// 打包优化
// 1. 准备排除项和对应的 cdn
let externals = {}
let cdn = { css: [], js: [] }
if (process.env.NODE_ENV === 'production') {
  externals = {
    // 包名: 引入的 js 脚本文件中的名称
    vue: 'Vue',
    'element-ui': 'ELEMENT',
    xlsx: 'XLSX'
  }
  cdn = {
    css: [
      'https://unpkg.com/element-ui/lib/theme-chalk/index.css' // element-ui css 样式表
    ],
    js: [
      // vue must at first!
      'https://unpkg.com/vue@2.6.12/dist/vue.js',
      'https://unpkg.com/element-ui@2.15.3/lib/index.js',
      'https://cdn.jsdelivr.net/npm/xlsx@0.16.6/dist/xlsx.full.min.js'
    ]
  }

  // 设置浏览器标签栏的 title
  const name = defaultSettings.title || 'vue Admin Template' // page title

  // 设置本地服务端口
  const port = process.env.port || process.env.npm_config_port || 8081 // dev port
  console.log('环境变量', process.env.VUE_APP_BASE_URL)
  module.exports = {
    // 打包后的 dist 中
    // index.html 中，会引入打包后的静态资源 js css
    // <script src="publicPath + 当前js资源的相对路径"></script>
    publicPath: './',
    // 输出文件目录
    outputDir: 'dist',
    // 输出静态文件二级目录
    assetsDir: 'static',
    lintOnSave: process.env.NODE_ENV === 'development',
    productionSourceMap: false,
    // 本地开发服务器配置
    devServer: {
      // 端口号
      port: port,
      // 项目启动后，自动打开浏览器
      open: true,
      // overlay：当出现编译器错误或警告时，在浏览器中显示全屏覆盖
      overlay: {
        // 如果要显示警告和错误
        warnings: false,
        errors: true
      },
      // 代理服务器
      proxy: {
        // 表示只要请求地址中有 /api 的时候，就会触发代理转发。
        '/api': {
          // target：要请求的真实接口地址。实际发送请求时，会使用 target 的值，替换掉原地址的域名部分
          // localhost:8081/api/sys/login  => http://ihrm.itheima.net/api/sys/login
          target: 'http://ihrm.itheima.net',
          // 是否跨域，需要设置此值为 true，才可以让本地服务代理我们发出的请求
          changeOrigin: true
          // 路径重写
          // localhost:8081/api/sys/login  => http://ihrm.itheima.net/sys/login
          // pathRewrite: {
          //   '/api': ''
          // }
        }
      }
    },
    configureWebpack: {
      externals: externals,
      name: name,
      resolve: {
        alias: {
          '@': resolve('src')
        }
      }
    },
    // configureWebpack: {
    //   // 2. webpack 配置 externals 配置项，排除打包
    //   externals: externals
    // },
    chainWebpack(config) {
      // it can improve the speed of the first screen, it is recommended to turn on preload
      config.plugin('preload').tap(() => [
        {
          rel: 'preload',
          // to ignore runtime.js
          // https://github.com/vuejs/vue-cli/blob/dev/packages/@vue/cli-service/lib/config/app.js#L171
          fileBlacklist: [/\.map$/, /hot-update\.js$/, /runtime\..*\.js$/],
          include: 'initial'
        }
      ])
      // 配置cdn
      config.plugin('html').tap(args => {
        args[0].cdn = cdn
        return args
      })
      // when there are many pages, it will cause too many meaningless requests
      config.plugins.delete('prefetch')

      // set svg-sprite-loader
      config.module
        .rule('svg')
        .exclude.add(resolve('src/icons'))
        .end()
      config.module
        .rule('icons')
        .test(/\.svg$/)
        .include.add(resolve('src/icons'))
        .end()
        .use('svg-sprite-loader')
        .loader('svg-sprite-loader')
        .options({
          symbolId: 'icon-[name]'
        })
        .end()

      config
        .when(process.env.NODE_ENV !== 'development',
          config => {
            config
              .plugin('ScriptExtHtmlWebpackPlugin')
              .after('html')
              .use('script-ext-html-webpack-plugin', [{
                // `runtime` must same as runtimeChunk name. default is `runtime`
                inline: /runtime\..*\.js$/
              }])
              .end()
            config
              .optimization.splitChunks({
                chunks: 'all',
                cacheGroups: {
                  libs: {
                    name: 'chunk-libs',
                    test: /[\\/]node_modules[\\/]/,
                    priority: 10,
                    chunks: 'initial' // only package third parties that are initially dependent
                  },
                  elementUI: {
                    name: 'chunk-elementUI', // split elementUI into a single package
                    priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
                    test: /[\\/]node_modules[\\/]_?element-ui(.*)/ // in order to adapt to cnpm
                  },
                  commons: {
                    name: 'chunk-commons',
                    test: resolve('src/components'), // can customize your rules
                    minChunks: 3, //  minimum common number
                    priority: 5,
                    reuseExistingChunk: true
                  }
                }
              })
            // https:// webpack.js.org/configuration/optimization/#optimizationruntimechunk
            config.optimization.runtimeChunk('single')
          }
        )
    }
  }
}

